If I keep taking all the eggs I collect and put them in the "favorite" egg box is it likely that one of the girls will go broody and sit on them?, or should I just leave them alone and start adding eggs after she goes broody?
I don't think a clutch of eggs has much chance of causing the hormonal change that makes them go broody. If I were going to try this, I'd use fake eggs (golf balls, plastic easter eggs, etc.) Your best chance of getting a nice bunch of chicks from a broody is collect the eggs elsewhere and, when one goes broody, placing them under her all at once.
On some of the other posts I've read there is talk of a "magic number" of eggs that a hen lays before she goes broody. I was kinda wondering if it's the amount she lays, or how many are available. They seem to be laying all the eggs in the same place anyway. I guess I'll just leave em alone.